Tamping devices



1959 H. P. TRAUTMAN 2,893,099

TAMPING DEVICES Filed June 22. 1953 2 Sheets-Sheet 1 INVEAN'TOR. Herman? Tray/M Arrow/5Y5 July7, 1959- H. P. TRAUTMAN 2,893,099

TAMPING DEVICES Filed June 22, 1953 I 2 Sheets-Sheer 2 h l lllt llllll llllslllll llllll I INVENTOR. Her/230:1 Baa/1 72a.

ATTORNEYS I 2,893,099 TAMPI NG DEVICES Herman P. Trautman, Saginaw, Mich, assignor to American-Marietta Company, Chicago, Ill.

Application June 22, 1953, Serial No. 363,240

3 Claims. (Cl. 25-37) This invention relates generally to mechanical tamping devices, and more particularly to tamping'machines of the type used in the manufacture of relatively large size pipe and tile to compact cementitious material as it is feed between forms.

' Devices of this general nature commonly employ one or more reciprocating tamping sticks which strike repeated blows to pack the material until a given consistency is attained, whence the resistance of the compacted material forces the sticks to slip in their holders, and thus automatically adjusts their stroke. In such devices, either the cementitious mass or the tamping mechanism must obviously be movable or revolvable one with relation to the other in order that the sticks may progressively and uniformly pack the entire circumferential wall surface of the pipe or tile. It has been found in practice that when the device is stopped during the tamping operation, as has been frequently necessary, the revolution of the moving elements is not immediately halted and the impetus of these elements will carry them some disance past the last point tamped, with the result that this portion of the pipe or tile is missed, and a void or weak spot appears in the tile when the forms are removed. Such imperfections result in the rejection of the tile upon inspection, or at least make necessary a costly and tedious patching operation.

One of the prime objects of my invention is to provide atamping device which need not be stopped during the tamping operation to vary the pressure which is applied to clamp the tamping sticks in their holders.

A further object of the invention is to design a highly flexible tamping device in which the pressure applied to the tamp sticks to frictionally retain them in a given position, is substantially unaffected by the rapid wear of the tamp sticks. It will be apparent that such a device need not be continually adjusted to compensate for this Wear in order to apply a constant pressure. I

V A further object of the invention is to design a de vice of the type described, which is more efiicient in operation and is capable of manufacturing a greater volume of pipe or tile of superior quality.

Another object of the invention is to provide a tamping machine in which the force which is applied to clamp the tamp sticks can be measured and set so that a definite force of measured intensity can be applied to pack pipe or tile of a given size to the desired consistency, thus eliminating cumbersome trial and error methods of arriving at and applying the proper clamping force with each individual machine.

Another object of the invention is to provide a tamping device in which the wear of the mechanism for clamping the tamp sticks will not affect the force with which the sticks are gripped.

A further object of the invention is to design a tamping device of simple andpractical design, and rugged and durable construction, which'is economical to manufac- 2,893,099 Patented July 7, 1959.

ture, assemble, and operate, and requires little or no maintenance. With the above and other objects in view, the present invention consists in the combination'and arrangement of parts, hereinafter more fully described, illustrated in the accompanying drawings, and more particularly pointed out in the appended claims, it being understood that changes may be made in the form, size, proportion, and

minor details of construction, without departing from the spirit, or sacrificing any of the advantages of the invention.

In the drawings:

Fig. 1 is a side elevational view of my tamping machine shown in tamping position packing cementitious material between a set of pipe forms, the forms being shown in section to indicate the construction of the pipe.

Fig. 2 is an enlarged, front elevational view showing the friction box or holder assembly which clamps the tamp sticks.

Fig. 3 is an enlarged, fragmentary, sectional, side ele-v vational view of the friction box assembly and the pressure actuated means for clamping the tamping sticks. therein, the broken lines indicating adjusted positions of the clamping mechanism.

Fig. 4 is an enlarged, sectional, top plan view taken on the line 44 of Fig. 2.

Referring now to the accompanying drawings in which I have shown the preferred embodiment of my invention,

shown a turntable 12 mounted on a base 13 which is provided with a spindle 14 as usual, said turntable being driven by means of a motor or the like through suitable reduction gearing (not shown). A cylindrical form 10 is mounted on the turntable 13 and rotates therewith, and an inner form or core 11 is suspended just above the face of the table and is held stationary with relation thereto, said suspension means being omitted from the drawings in the interest of clarity.

The tamp sticks 15 are supported for reciprocal travel in the machineT in a manner to be presently described, the lower'end of the sticks extending into the interstitial space between the walls of the form as the device is operated, so that the entire circumferential area of the cementitious mass is progressively and uniformly tamped as the machine is driven.

The tamping machine T includes a post or standard 16 having a base 17, a main support bracket 18 being adjustably mounted on the post, said bracket being formed with laterally projecting arms 19 which support the tamping mechanism in position over the interstitial space between the forms 10 and 11. Extensions arms 20 project from the opposite side of the bracket 18, and slide bearings 21 are provided on the outer-ends thereof to support a friction box or tamp holder 22 which is mounted for reciprocal travel therein. The friction box 22 is driven by a motor 23 mounted on the bracket 18, said motor having a pulley 24 on the armature shaft 25 thereof for driving a shaft 26 which is journaled in bearings 27 provided on the bracket 18.

A pulley 28 is mounted on the shaft 26 and is drive.

ingly connected to pulley 24 by means of belts 29. A crank wheel 30 with an offset crank pin 31 thereon is mounted on the opposite end of the shaft 26, and a pitman rod 32 connects the pin 31 with a pin 33 provided on the friction box 22 to reciprocate the latter at a relatively high speed.

The friction box comprises a housing 22, preferably but not necessarily rectangular in cross section in which the tamp sticks 15 are mounted on opposite sides of a central partition 34. These sticks 15 are preferably formed of a relatively inexpensive wear resistant wood, but could, of course, be formed of any other suitable material, and metal shoes 35 are secured on the lower ends of the sticks as shown. Elongated openings 36 and 37 are pro videdin the front and rear walls of the housing 22 to expose the sticks 15 to the clamping pressure of a pair of U-shaped friction plates 38 and 39. The plates 33 and 39 are supported by a pair of straps 40 provided on the sides of the housing 22, which straps are slotted or bi furcated at both ends as at 41 and42.

Trunnions 43 on the rear plate 38 serve to support it in the slots 41, and a transversely disposed pin 44 extends through openings in the front plate 39 and supports the plate 39 in the slots 42. The plates 38 and 39 are pressed into engagement with the tamping sticks 15 by arcuate springs 45 and 46 which are compressed by a pneumatically operated diaphragm and plunger assembly D in a manner to be presently described.

The diaphragm and plunger assembly D is of conven tionaldesign and includes a pair of dish-shaped casings 47 and 48 secured together as at 49, a fabric diaphragm 50, carrying the operating stem or plunger 51, dividing the casing assembly into two compartments as usual. Theplunger 51 extends through a central opening 52 provided in a bearing 53 formed on the casing 48 and extends through the hub 54 of a laterally disposed yoke member 55. The hub 54 of the yoke 55 is formed with an enlarged bore 56 to slidably accommodate the enlarged end 57 of the plunger or stem 51. Rearward movement of the plunger 51, of course, is limited by the length of the bore 56. Tie rods 58 formed with eyes 59 on the front ends thereof connect the pin 44 and yoke 55 respectively, the rear ends of the rods 58 having nuts 60 thereon which receive the threaded stems 61 of the clevises 62 which connect to the yoke member 55. A roller 63 is mounted on the pin 44 adjacent the spring 46, and it will be obvious that when the plunger 51 is moved forwardly to compress the spring 45 and transmit pressure to the clamping plate 38, the roller 63 will in turn be moved rearwardly to compress the spring 46 and transmit an equal pressure to the clamping plate 39.

A flexible pneumatic hose 64 leads into a fitting 64a on the casing to transmit pressure from a suitable source of supply (not shown) to operate the plunger 51. To reduce whipping of the hose on reciprocation of the friction box 22, it is anchored to the main support bracket at 65 and thence leads upwardly as shown.

A pressure gauge 67 is interposed in the line 64 di rectly adjacent a pressure reducing valve with an air cleaner at 68, and a shut off valve 69, and an air release valve 70 are similarly provided in the line as shown. These controls are conventional and permit the clamping pressure applied to the tamp sticks 15 to be varied as desired.

In Fig. l of the drawings, I have shown the formation of a pipe in which a pair of spacedreinforcing cages 71 and 72 are employed, but obviously, the apparatus is capable of making pipe of varying size and-design, either with or without reinforcing. In the present illustration, the core form 11 which islowered from above when the tamping machine is swung out of the way is held stationary by means (not shown), while the. turntable .125.re-

volves. The outerspace contiguous'to the outer revolving form is tamped by the outer shoe 35; thecentral space between'the reinforcing cages 71 and-72is tamped by the inner shoe 35, and the inner space contiguous to the stationary core 11 is finished by the troweling action of the revolving concrete mass against the core 11.

In operation, the wet cementitious material is continuously fed from a trough 73, to the space between the forms 10 and 11 as the first-mentioned form revolves. The tamp sticks 15 which begin their stroke near the floor of the turntable are automatically worked upwardly relative to the friction box holder as the tamping operation proceeds. It will be apparent that as the material is tamped to a consistency of sufficient resistance to overcome the force of the air pressure holding the sticks, the sticks which are frictionally secured will be forced upwardly relative to the friction box holder. Thus, the condition of the material itself automatically adjusts the effective stroke of the sticks, although the stroke of the friction box holder, of course, remains constant. During the tamping operation, the pressure exerted on the tamping sticks 15 can be changed at will without shutting down the machine, stopping the turntable 12, and cutting off the flow of material through the trough 73. Further, it is not necessary to stop these elements to adjust the device as a consequence of the rapid wear of the tamping sticks or to replace sticks as often as previously.

It will thus be readily apparent that I have perfected a tamping machine which is far more efficient in operation and permits the manufacture of superior pipe or tile of uniform texture which are free of voids or weak spots.

It is to be understood that various changes may be made in the size, form, and design of the various components of the device without departing from the spirit of the invention or the scope of the subjoined claims, and it is intended that the description and drawings are to be interpreted as illustrative rather than limiting. For example, devices may be built embodying the instant principles in which one tamping shoe or more than a pair of tamping shoes are employed. In other designs, the tamping mechanism may revolve relative to the forms or the tamping may be horizontal rather than vertical.

What I claim is:

1. In a tamping device for compacting material between forms, a tamp holder, support means to position said holder relative to said forms, parallel disposed tamp sticks in said holder, means for actuating said holder and the tamp sticks therein rapidly to-and-fro to compact said material, a friction plate in engagement with the outer surface of each tamp stick, resilient means positioned adjacent each friction plate, a pressure operated diaphragm having a plunger to compress the resilient means adjacent one of said friction plates and exert a pressure thereon to retain said stick in said holder, and

means on said plunger movable in a direction opposite thereto upon actuation thereof to compress the resilient means in engagement with a second friction plate and exert pressure thereon to frictionally retain a second tamp stick in said holder.

2. The combination defined in claim 1 in which said means on said plunger comprises a yoke, a cross pin supporting the second friction plate, tie rods connecting said yoke and cross pin, and means on said pin for compressing said resilient means upon=movement of said yoke.

3. In a tamping device for compacting a revolvingcementitious mass between forms, a tamp holder having a central partition, support means to position said holder relative to said forms, a pair of parallel disposed tamp sticks in said holder on opposie side of said partition, means for reciprocating said holder to compact the material, a friction plate in engagement with the outersurface of each tamp stick, an arcuate spring positioned to bear against the outer surface of each friction plate, a pressure operated diaphragm, a stern fixed thereto for compressing one of said springs and exerting pressure on the adjacent friction plate to frictionally clamp one of said. sticks against the one side of said partition, a

yoke in engagement with the casing of said diaphragm slidably disposed on said stem, a cross pin supporting the other friction plate, adjustable tie rods connecting the yoke and cross pin, and a roller on said cross pin in engagement with the opposite spring to compress said spring when the plunger is operated and the yoke is moved in an opposite direction, said roller clamping the second tamp stick against the opposite wall of said partition.

References Cited in the file of this patent UNITED STATES PATENTS Easterday Jan. 20, 1925 Alrnquist Dec. 14, 1926 Tuerck Jan. 2, 1940 Wallace May 20, 1941 Terry et a1. Jan. 12, 1943 Tankovich Sept. 27, 1949 

